1. Field of the Invention
The present invention relates in general to mechanical devices for removing the tassels from corn plants, and more specifically, to a crop height sensing assembly for a control system that automatically adjusts the vertical position of such devices relative to the height of the corn plants being detasseled.
2. Description of the Prior Art
Various types of mechanical corn detasseling devices are known in the art, and these devices are becoming more common in replacing the manual removal of tassels. Although most mechanical detasselers operate satisfactorily in removing tassels when the corn plants are substantially uniform in height, many of them are ineffective to efficiently remove tassels from corn plants of varying heights.
The most common means presently employed for handling corn plants of varying heights comprise vertically adjustable detasseling devices that are powered for up or down movement in response to a manual control by the operator of the detasseling implement. However, the effectiveness of such manual control is directly dependent upon driving abilities and alertness of the operator. As a result, detasseling takes place at a reduced rate of the speed corresponding to the operator's reaction time in manually adjusting the detasseling devices.
Thus a need exists for an automatic detasseling apparatus that is vertically adjusted automatically relative to the varying heights of the corn plants encountered. To provide such an apparatus that is effective and efficient requires a sensor assembly that can readily sense the height of the corn plants and provide a sensing signal that is relative to the varying heights of the corn plants encountered. Canadian Pat. No. 778,092 discloses an automatic height adjusting control for a single bar of a combined for harvesting wheat, oats, barley and the like. Such control employs a number of sensing units with horizontally disposed sensor arms for engaging the crop at different heights to provide a crop height sensing signal. Although such sensing units appear to be satisfactory for the above mentioned crops that have a plurality of plants closely adjacent to one another, they do not provide satisfactory sensing of the height of corn plants that are individually aligned in relatively widely spaced apart rows.